diff --git a/src/woodshop/viewer.py b/src/woodshop/viewer.py
index e132e43..3c9921d 100644
--- a/src/woodshop/viewer.py
+++ b/src/woodshop/viewer.py
@@ -102,6 +102,16 @@ def run(scene_path: Path | None = None, poll_s: float = 0.3) -> None:
     plotter.set_background("#2b2b2b")
     plotter.enable_parallel_projection()
 
+    # Let closing the window (X button) or pressing q/Escape end the loop.
+    closed = {"flag": False}
+    def _on_close():
+        closed["flag"] = True
+    for key in ("q", "Escape"):
+        try:
+            plotter.add_key_event(key, _on_close)
+        except Exception:
+            pass
+
     last_mtime = -1.0
     scene = Scene.load(scene_path) if scene_path.exists() else Scene()
     _render(plotter, scene)
@@ -109,6 +119,9 @@ def run(scene_path: Path | None = None, poll_s: float = 0.3) -> None:
     plotter.show(interactive_update=True, auto_close=False)
 
     while True:
+        # Stop if the render window has been closed by any means.
+        if closed["flag"] or getattr(plotter, "_closed", False) or plotter.render_window is None:
+            break
         try:
             mtime = scene_path.stat().st_mtime if scene_path.exists() else 0.0
             if mtime != last_mtime:
@@ -119,9 +132,14 @@ def run(scene_path: Path | None = None, poll_s: float = 0.3) -> None:
             time.sleep(poll_s)
         except KeyboardInterrupt:
             break
-        except Exception:  # window closed
+        except Exception:  # window destroyed mid-update
             break
 
+    try:
+        plotter.close()
+    except Exception:
+        pass
+
 
 def main(argv: list[str] | None = None) -> int:
     ap = argparse.ArgumentParser(prog="woodshop-view", description="Live WoodShop 3D viewport.")